In open systems where the components, i.e. the agents and the resources, may be unknown at design time, or in dynamic and self-organizing systems evolving with time, there is a need to enable the agents to communicate their intentions with respect to future activities and resource utilization to resolve coordination issues dynamically. Ideally, we would like to allow ad-hoc interaction, where two standalone independently-designed systems are able to coordinate whenever a need arises. The Semantic Web based approach presented in this paper aims at enabling agents to coordinate without assuming any design-time ontological alignment of them. An agent can express an action intention using own vocabulary, and through the process of dynamic ontology linking other agents will be able to arrive at a practical interpretation of that intention. We also show how our approach can be realized on top of the Semantic Agent Programming Language.